Now that K-pop is experiencing such success on its own terms, the questions it faces are changing. Should K-pop acts release English-language music? To what degree should they focus on collaborations with non-Korean artists?

Also this week: a look at the music of BTS (and the solo album of group leader RM); and how recent releases from Super Junior, NCT 127 and Blackpink are moving the genre and sound in new directions.